<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>媒体查询</title>
  <style>
    /* 从小到大  >=320px 的一种样式 */
    @media screen and (min-width:320px) {
      html{
        font-size: 12px;
      }
      body{
        background-color: #16baaa;
      }
    }
    /* 从小到大  >=700px 的一种样式*/
    @media screen and (min-width:700px){
      html{
        font-size: 16px;
      }
      body{
        background-color: #b4f39d;
      }
    }
    /* 从小到大  >=1080px 的一种样式*/
    @media screen and (min-width:1080px){
      html{
        font-size: 22px;
      }
      body{
        background-color:#488537 ;
      }
    }
    div{
      width: 10rem;
      height: 10rem;
      margin: 0 auto;
      background-color: #005971;
    } 
    /* media="srceen and (min-width:320px)" */
  </style>
  <link rel="stylesheet" href="../css/320px.css" media="screen and (min-width: 320px)">
  <link rel="stylesheet" href="../css/640px.css" media="screen and (min-width: 640px)" >
</head>
<body>
    <div></div>
    <div class="media_div"></div>
    <div class="media_div"></div>
</body>
</html>